Retrieving Media from a Content Resolver

在设备中查找音乐：

ContentResolver contentResolver = getContentResolver();
Uri uri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
Cursor cursor = contentResolver.query(uri, null, null, null, null);
if (cursor == null) {
// query failed, handle error.
} else if (!cursor.moveToFirst()) {
// no media on the device
} else {
int titleColumn = cursor.getColumnIndex(android.provider.MediaStore.Audio.Media.TITLE);
int idColumn = cursor.getColumnIndex(android.provider.MediaStore.Audio.Media._ID);
do {
long thisId = cursor.getLong(idColumn);
String thisTitle = cursor.getString(titleColumn);
// ...process entry...
} while (cursor.moveToNext());
}

在MediaPlayer中使用它：

long id = /* retrieve it from somewhere */;
Uri contentUri = ContentUris.withAppendedId(
    android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI, id);

mMediaPlayer = new MediaPlayer();
mMediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
mMediaPlayer.setDataSource(getApplicationContext(), contentUri);

// ...prepare and start...